observe_rsc_update/3

An updated resource is about to be persisted. Observe this notification to change the resource properties before they are persisted.

The props are the resource’s props _before_ the update, but _after_ filtering and sanitization. The folded value is {ok, UpdateProps} for the update itself.

Type:

foldr

Return:

{ok, UpdateProps} or {error, term()}

#rsc_update{} properties:

• action: insert|update

• id: m_rsc:resource_id()

• props: m_rsc:props()

An updated resource is about to be persisted. Observe this notification to change the resource properties before they are persisted.

Arguments

#rsc_update

action

Either insert or update.

id

Id of the resource.

props

Map with resource properties.

{ok, UpdateProps} | {error, Reason}

And/remove resource properties before the update is persisted.

Context

Site context

Example

Add a property before the resource is persisted:

observe_rsc_update(#rsc_update{action = insert, id = Id}, {ok, Props}, Context) ->
    %% Set an extra property
    {ok, Props#{ <<"extra_property">> => <<"special value!">> }}.
observe_rsc_update(#rsc_update{action = insert, id = Id}, {error, _} = Error, Context) ->
    Error.